High-frequency alternating current waveforms in the kilohertz range (KHFAC) can provide a temporary nerve conduction block that does not provide a lasting effect on conduction. Similarly, direct current (DC) signals also can block conduction in the nerve. However, even at small amplitudes (e.g., a low micro Ampere (μA) range), after prolonged or repeated application, DC signals can damage the nerve tissue, leading to a lasting effect on conduction. For example, the lasting effect on conduction can be noticeable as a persistent reduction in nerve conductivity, even after the application of any kind of electric waveform has ended. This persistent reduction in nerve conductivity can be related to changes in pH levels at and/or within the nerve in close proximity to the electrode and can coincide with the damage of neural tissue.
Unintentional DC signals can contaminate KHFAC waveforms, leading to unexpected nerve block and/or damage. With lower frequency waveforms, techniques like additional capacitance and/or shunting resistance can be applied between the waveform generator and the electrode to substantially mitigate unintentional DC signals. However, these approaches are not feasible and/or not practical for use with higher frequency waveforms like KHFAC waveforms, especially current-controlled KHFAC waveforms. For example, the higher frequency waveforms do not allow the capacitors sufficient time to discharge the DC imbalance between stimulation pluses, so the unintentional DC signals that contaminate KHFAC waveforms cannot be substantially eliminated.